Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2018/r/gumushane/18262
  Effects of manufacturing type on control performance of multiple tunedmass dampers under harmonic excitation

  Kahya, Volkan; Araz, O.

  Using different optimization techniques, the optimum characteristics of multiple tuned mass dampers (MTMD) for reducing the dynamic response of primary structure due to various excitations are studied by many researchers. In this paper, the five practical MTMD models are considered which consist of different combinations of the mass, damping, stiffness coefficient and damping ratio in the MTMD. The criteria selected for the optimality is the minimization of the maximum value of the displacement dynamic magnification factor (DMF) of the primary structure with the MTMD system under external harmonic excitation. The optimum parameters of the MTMD systems are investigated using Sequential Quadratic Programming (SQP). Results obtained illustrate that the optimum MTMD-1 and MTMD-4 have nearly the same control performance and provide higher effectiveness than all the other types of MTMDs of the same mass ratio in reducing the displacement response of primary structure. Finally, a robustness analysis of optimally designed MTMD systems to investigate their performance under errors in the tuned frequencies is also performed in detail.

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• MakaleYalnız künye2018/r/gumushane/18193
  Dynamic response of a reinforced concrete minaret

  Tonyali, Z.; Günaydın, M.

  Minarets are one of the specific structure types used commonly in Islamic Countries. Many minarets weredamaged or collapsed during catastrophic events like earthquake. During an earthquake to understand theminarets’ behavior are so important since dynamic response of these structures depends on a detailedunderstanding of their structural characteristics, such as geometrical shape, supporting system, mode shapes,natural frequencies and modal damping ratio etc. This paper examines in detail a Turkish style reinforcedconcrete (RC) minaret, its finite element modeling, modal analysis and earthquake analysis. A reinforcedconcrete minaret which is generally built in Turkey is selected as an application. Three-dimensional (3D)model of the minaret and its modal analysis are performed to obtain analytical frequencies and mode shapesusing ANSYS finite element program. The minaret’s linear transient analysis is carried out using the 1992Erzincan earthquake ground motion record to obtain the earthquake behavior of the minaret. At the end ofthe study, the calculated displacement responses and maximum-minimum principal stresses concentrationsfor the minaret are briefly discussed and illustrated.

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• MakaleAçık Erişim2018/r/gumushane/18191
  Investigation of the contact problem for a partial functionally gradedlayer by using finite element method

  Kaya, Y.; Polat, A.; Bora, P.; Bendine, K.; Özşahin, T.ş.

  The difficulty of producing functionally graded materials (FGM) and the fact that they are more expensive than homogeneous materials emerge as an industrial problem. The starting point of this study is to investigate alternative solution methods that will contribute to the mentioned problem. In parallel, the analysis of the contact problem for a layer, which is loaded by a rigid block and resting on the elastic half plane, is presented in this paper. Only the area under the block is considered as FGM, the other parts are considered homogeneous material, unlike the studies in the literature. There is no analytical solution for this study and it is compared with the solution which is completely functionally graded (FG) layer in the literature by using finite element method (FEM). Material properties of the FG layer are defined by the macro added to the ANSYS program. The analysis for the partial FG layer were compared with the completely FG layer analysis as figures and tables, and as a result it was predicted that partial FGM could be used for the static problems and may also be practical applications in the industry.

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